Lecture 7: Desert ecosystems and caryophylalles Flashcards

Question

What is an ochrea?

Answer 1

A sheathing stipule

Answer 2

- Perennial, herbaceous plant - Invasive especially along banks of waterways - Not very shade tolerant - Very good at establishing itself on coarse soil

Answer 3

Caryophyllales

Answer 4

Carnivorous plants not traditionally associated with Caryophyllids, but they form a claude with them in phylogenetic trees based on both nuclear and chloroplast DNA sequences Unique habitats with challenging nutrient acquisition common in order Often found in fens and bogs Flower not important in identification

Answer 5

- Small plants with basal rosette of leaves - Leaves with glandular hairs to capture insects (insectivorous) - Perfect flowers

Answer 6

Low levels of precipitation; most less than 10 inches a year Potential evapotranspiration exceeds precipitation Can occur at different average annual temperatures and precipitation levels - some areas lose water more than others, number of hours of sunlight, etc. impact this In North American desert regions, there are several mountain ranges/isolated mountains - these provide large gradients in temperature and precipitation/moisture availability Water deficit -->

Answer 7

At equator high sun intensity causes evaporation and a moist warm air mass to rise As it rises, this air mass moves away from the equator, cools and releases moisture (in wet tropics region) Cool, dry air falls at 30 degreed N or S latitude, causing bands of deserts at these regions

Answer 8

Large fluctuations in day/night temperatures because few clouds to capture reflected infrared radiation, so no sun, no heat Exposed soils (because of incomplete cover of vegetation) lead to high rates of weathering and erosion (since more sun exposure, more temperature fluctuations, exposure to wind) and very low OM content Some deserts have salt concentrated at the surface because of evaporation from the soil bringing salts to the surface and not enough heavy rains to leach the salts out of the soil

Answer 9

Mutualistic/facilitation types of exchange are important/more frequent than in more productive environments for plant growth Competition for resources still occurs, but the harsh growing conditions mean that being close to a neighbour might be more of an aid than a hinderance Main positive exchanges: protection from herbivores, microhabitat of shade, wind blocking, and hydraulic lift from deeper rooted neighbours

Answer 10

Topography, continental location, geologic history, etc.

Answer 11

Great Basin Mojave Sonoran Chihuahuan

Answer 12

Topography

Answer 13

Northern Shrubby woody plants dominate Less diverse than other desert regions Western side of NA

Answer 14

Mid-elevation: dominated by woodlands Lower elevations: sparse grasslands to desert shrub

Answer 15

Sagebrush --> deep roots bring water to the surface

Answer 16

During the last glaciation, these basins were flooded, but as the climate dried, the lowest part of the basin became dry, salty deposit where few plants can grow

Answer 17

High diversity Habitats vary greatly with topography Indicator species: Cactaceae Spring habitats harbor remnants of the flora that prospered when the region was wetter during and after the last glaciation Rivers and streams are also present

Answer 18

Lower lands: Fabaceae trees common Mesquite Cactaceae Asteraceae Papaveraceae Salicaceae etc.

Answer 19

A transitional desert at fairly high elevations, parts with a good water supply, but also Death Valley Joshua tree is the indicator species for this desert Yucca (Asparagaceae family)

Answer 20

High-elevation warm desert in Texas, New Mexico and Mexico Limestone and calcareous soils common Rich diversity of Cactaceae and Asparagaceae: Agovoideae subfamily Indicator species: Agave lechuguilla